Method and apparatus for restricting flow through an opening in the side wall of a body lumen, and/or for reinforcing a weakness in the side wall of a body lumen, while still maintaining substantially normal flow through the body lumen

ABSTRACT

A method for making a device for causing thrombosis of an aneurysm, wherein said device comprises a single elastic filament configurable between (i) an elongated, substantially linear configuration, and (ii) a longitudinally-contracted, substantially three-dimensional configuration, said method comprising:
         providing a sheet of shape memory material;   producing a single filament, two-dimensional interim structure from said sheet of shape memory material;   mounting said single filament, two-dimensional interim structure to a fixture so that said single filament, two-dimensional interim structure is transformed into said longitudinally-contracted, substantially three-dimensional configuration; and   heat treating said single filament, two-dimensional interim structure while it is mounted to said fixture so as to produce said device in its longitudinally-contracted, substantially three-dimensional configuration.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

This patent application:

(i) is a continuation-in-part of prior U.S. patent application Ser. No.12/657,598, filed Jan. 22, 2010 now U.S. Pat. No. 8,663,301 by HowardRiina et al. for METHOD AND APPARATUS FOR RESTRICTING FLOW THROUGH ANOPENING IN THE SIDE WALL OF A BODY LUMEN, AND/OR FOR REINFORCING AWEAKNESS IN THE SIDE WALL OF A BODY LUMEN, WHILE STILL MAINTAININGSUBSTANTIALLY NORMAL FLOW THROUGH THE BODY LUMEN, which patentapplication (a) is in turn a continuation-in-part of prior U.S. patentapplication Ser. No. 12/332,727, filed Dec. 11, 2008 now U.S. Pat. No.8,728,141 by Howard Riina et al. for METHOD AND APPARATUS FOR SEALING ANOPENING IN THE SIDE WALL OF A BODY LUMEN, AND/OR FOR REINFORCING AWEAKNESS IN THE SIDE WALL OF A BODY LUMEN, WHILE MAINTAININGSUBSTANTIALLY NORMAL FLOW THROUGH THE BODY LUMEN, which in turn claimsbenefit of prior U.S. Provisional Patent Application Ser. No.61/007,189, filed Dec. 11, 2007 by Howard Riina et al. for DEPLOYABLEBLOCKING SPHERE; (b) claims benefit of prior U.S. Provisional PatentApplication Ser. No. 61/205,683, filed Jan. 22, 2009 by Jeffrey Milsomet al. for METHOD AND APPARATUS FOR SEALING AN OPENING IN THE SIDE WALLOF A BODY LUMEN, AND/OR FOR REINFORCING A WEAKNESS IN THE SIDE WALL OF ABODY LUMEN, WHILE MAINTAINING SUBSTANTIALLY NORMAL FLOW THROUGH THE BODYLUMEN; and (c) claims benefit of prior U.S. Provisional PatentApplication Ser. No. 61/277,415, filed Sep. 24, 2009 by Howard Riina etal. for METHOD AND APPARATUS FOR RESTRICTING AN OPENING IN THE SIDE WALLOF A BODY LUMEN, AND/OR FOR REINFORCING A WEAKNESS IN THE SIDE WALL OF ABODY LUMEN, WHILE MAINTAINING SUBSTANTIALLY NORMAL FLOW THROUGH THE BODYLUMEN; and

(ii) claims benefit of prior U.S. Provisional Patent Application Ser.No. 61/470,733, filed Apr. 1, 2011 by Howard Riina et al. for FLOWDIVERTERS.

The six (6) above-identified patent applications are hereby incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to medical procedures and apparatus in general,and more particularly to medical procedures and apparatus forrestricting flow through an opening in the side wall of a body lumen,and/or for reinforcing a weakness in the side wall of a body lumen,while still maintaining substantially normal flow through the bodylumen.

BACKGROUND OF THE INVENTION

The human body consists of many different anatomical structures. Amongthese anatomical structures are the blood vessels which circulate bloodthroughout the body, i.e., the arteries which deliver oxygenated bloodto the end tissues and the veins which return oxygen-depleted blood fromthe end tissues.

In some cases, a blood vessel can become weakened, thereby causing theside wall of the blood vessel to balloon outwardly so as to create ananeurysm. See, for example, FIGS. 1-3, which show various types ofaneurysms, e.g., a fusiform aneurysm (FIG. 1), where the aneurysmextends around a substantial portion of the circumference of a bloodvessel; a lateral aneurysm (FIG. 2), where the aneurysm extends out of alimited portion of the side wall of a blood vessel, with a well-definedneck; and a bifurcation aneurysm (FIG. 3), where the aneurysm extendsout of the apex of a bifurcation of a blood vessel. For purposes of thepresent invention, all of these aneurysms (e.g., fusiform aneurysms,lateral aneurysms and/or bifurcations aneurysms) are considered toextend out of the side wall of a blood vessel.

Aneurysms can present a serious threat to the patient, since they mayenlarge to the point of rupture, thereby resulting in a rapid anduncontrolled loss of blood. Depending upon the size and location of theaneurysm, the aneurysm can be life-threatening.

By way of example but not limitation, an intracranial aneurysm can befatal if rupture occurs. Given the life-threatening nature of suchintracranial aneurysms, these aneurysms have traditionally been treatedwith an open craniotomy and microsurgical clipping. This proceduregenerally involves placing a small titanium clip across the neck of theaneurysm, thus isolating the aneurysm from blood flow and inhibitingsubsequent rupture (or re-rupture). This clipping procedure is typicallydone under direct visualization, using an operating microscope.

More recently, minimally-invasive techniques have also been used totreat both ruptured and un-ruptured brain aneurysms. Theseminimally-invasive techniques generally employ interventionalneuroradiological procedures utilizing digital fluoroscopy. Moreparticularly, these interventional neuroradiological proceduresgenerally use X-ray visualization to allow the surgeon to place amicrocatheter within the dome of the aneurysm. With the microcatheter inplace, detachable coils are then deployed within the dome of theaneurysm, thereby reducing blood velocity within the dome of theaneurysm and causing thrombosis of the aneurysm so as to preventsubsequent rupture (or re-rupture). However, this coil-depositingprocedure has a number of drawbacks, including the risk of coilherniation into the lumen of the blood vessel; the risk of coilmigration out of the aneurysm and into the blood vessel, with subsequentdownstream migration; the risk of aneurysm rupture; etc.

As a result, a primary object of the present invention is to provide anew and improved device, adapted for minimally-invasive, endoluminaldelivery, which may be used to restrict blood flow to an aneurysm whilestill maintaining substantially normal blood flow through the bloodvessel.

Another object of the present invention is to provide an expandablespherical structure, comprising an open frame with a flow-restrictingface (i.e., a closed face or a face having a high strut density), whichmay be used to restrict flow through an opening in a side wall of ablood vessel while still maintaining substantially normal blood flowthrough the blood vessel.

Another object of the present invention is to provide an expandablespherical structure, comprising an open frame with a flow-restrictingface (i.e., a closed face or a face having a high strut density), whichmay be used to reinforce a weakness in a side wall of a blood vesselwhile still maintaining substantially normal blood flow through theblood vessel.

Another object of the present invention is to provide an expandablespherical structure, comprising an open frame with a flow-restrictingface (i.e., a closed face or a face having a high strut density), whichmay be used to restrict flow through an opening in the side wall of alumen other than a blood vessel, and/or so as to reinforce a weakness ina side wall of a lumen other than a blood vessel, while stillmaintaining substantially normal flow through the lumen.

Another object of the present invention is to provide an expandablespherical structure which may be used to facilitate the deployment ofdetachable coils and/or other embolic material into the interior of ananeurysm while still maintaining substantially normal flow through theblood vessel.

And another object of the present invention is to provide a method formanufacturing the novel device of the present invention.

SUMMARY OF THE INVENTION

These and other objects of the present invention are addressed throughthe provision and use of a novel expandable spherical structure, and amethod for making the same.

In one form of the invention, there is provided an expandablesubstantially spherical structure for deployment in a blood vessel orother body lumen, comprising:

an open frame formed out of a closed loop of filament and configured toassume (i) a collapsed configuration in the form of a substantiallytwo-dimensional elongated loop structure so as to facilitate insertioninto the blood vessel or other body lumen, and (ii) an expandedconfiguration in the form of a three-dimensional substantially sphericalstructure so as to facilitate retention at a site in the blood vessel orother body lumen; and

a flow-restricting face carried by the open frame;

wherein the open frame is configured so as to permit substantiallynormal flow therethrough when the open frame is in its expandedconfiguration, and further wherein the flow-restricting face isconfigured so as to restrict flow therethrough.

In another form of the invention, there is provided a system forrestricting flow to an opening in the side wall of a blood vessel orother body lumen and/or reinforcing a weakness in the side wall or apexof a bifurcation of the blood vessel or other body lumen, whilemaintaining substantially normal flow through the blood vessel or otherbody lumen, comprising:

an expandable substantially spherical structure for deployment in theblood vessel or other body lumen, comprising:

-   -   an open frame formed out of a closed loop of filament and        configured to assume (i) a collapsed configuration in the form        of a substantially two-dimensional elongated loop structure so        as to facilitate insertion into the blood vessel or other body        lumen, and (ii) an expanded configuration in the form of a        three-dimensional substantially spherical structure so as to        facilitate retention at a site in the blood vessel or other body        lumen; and    -   a flow-restricting face carried by the open frame;    -   wherein the open frame is configured so as to permit        substantially normal flow therethrough when the expandable open        frame is in its expanded configuration, and further wherein the        flow-restricting face is configured so as to restrict flow        therethrough; and

an installation tool for carrying the expandable substantially sphericalstructure to a deployment site, wherein the installation tool comprises:

-   -   an elongated structure having a first mount for seating a first        portion of the closed loop and a second mount for seating a        second portion of the closed loop, the first mount and the        second mount being movable relative to one another between a        first position and a second position so that (i) when the first        portion of the closed loop is seated in the first mount and the        second portion of the closed loop is seated in the second mount        and the first mount and second mount are in their first        position, the open frame is in its expanded substantially        spherical configuration, and (ii) when the first portion of the        closed loop is seated in the first mount and the second portion        of the closed loop is seated in the second mount and the first        mount and second mount are in their second position, the open        frame is in its collapsed and elongated configuration.

In another form of the invention, there is provided a method forrestricting flow to an opening in the side wall of a body lumen whilemaintaining substantially normal flow through the body lumen,comprising:

providing an expandable substantially spherical structure for deploymentin the body lumen, comprising:

-   -   an open frame formed out of a closed loop of filament and        configured to assume (i) a collapsed configuration in the form        of a substantially two-dimensional elongated loop structure so        as to facilitate insertion into the blood vessel or other body        lumen, and (ii) an expanded configuration in the form of a        three-dimensional substantially spherical structure so as to        facilitate retention at a site in the blood vessel or other body        lumen; and    -   a flow-restricting face carried by the open frame;    -   wherein the open frame is configured so as to permit flow        therethrough when the open frame is in its expanded        configuration, and further wherein the flow-restricting face is        configured so as to restrict flow therethrough;

delivering the expandable substantially spherical structure to a therapysite within the body lumen while the open frame is in its collapsedconfiguration; and

transforming the expandable substantially spherical structure from itscollapsed configuration to its expanded configuration so that theexpandable substantially spherical structure is securely lodged in thebody lumen, with the flow-restricting face of the expandablesubstantially spherical structure positioned so as to restrict flow tothe opening in the side wall of the body lumen and with the open framepermitting flow through the body lumen.

In another form of the invention there is provided an expandablesubstantially spherical structure for deployment in a blood vessel orother body lumen, comprising:

an open frame configured to assume a collapsed configuration and anexpanded configuration;

a flow-restricting face carried by the open frame; and

a plurality of stabilizing legs attached to, and extending away from,the open frame;

wherein the open frame and the plurality of stabilizing legs areconfigured so as to permit substantially normal flow therethrough whenthe open frame is in its expanded configuration, and further wherein theflow-restricting face is configured so as to restrict flow therethrough.

In another form of the invention, there is provided a method forrestricting flow through an opening in the side wall of a body lumenwhile maintaining substantially normal flow through the body lumen,comprising:

providing an expandable substantially spherical structure for deploymentin the body lumen, comprising:

-   -   an open frame configured to assume a collapsed configuration and        an expanded configuration;    -   a flow-restricting face carried by the open frame; and    -   a plurality of stabilizing legs attached to, and extending away        from, the open frame;    -   wherein the open frame and the plurality of stabilizing legs are        configured so as to permit flow therethrough when the open frame        is in its expanded configuration, and further wherein the        flow-restricting face is configured so as to restrict flow        therethrough;

delivering the expandable substantially spherical structure to a therapysite within the body lumen while the open frame is in its collapsedconfiguration and the plurality of stabilizing legs are in a collapsedconfiguration; and

transforming the expandable substantially spherical structure from itscollapsed configuration to its expanded configuration, and transformingthe plurality of stabilizing legs from their collapsed configuration toan expanded configuration, so that the expandable substantiallyspherical structure is securely lodged in the body lumen, with theflow-restricting face of the expandable substantially sphericalstructure positioned so as to restrict flow to the opening in the sidewall of the body lumen and with the open frame and the plurality ofstabilizing legs permitting flow through the body lumen.

In another form of the invention, there is provided a method for makinga device for causing thrombosis of an aneurysm, wherein said devicecomprises a single elastic filament configurable between (i) anelongated, substantially linear configuration, and (ii) alongitudinally-contracted, substantially three-dimensionalconfiguration, said method comprising:

providing a sheet of shape memory material;

producing a single filament, two-dimensional interim structure from saidsheet of shape memory material;

mounting said single filament, two-dimensional interim structure to afixture so that said single filament, two-dimensional interim structureis transformed into said longitudinally-contracted, substantiallythree-dimensional configuration; and

heat treating said single filament, two-dimensional interim structurewhile it is mounted to said fixture so as to produce said device in itslongitudinally-contracted, substantially three-dimensionalconfiguration.

In another form of the invention, there is provided a device forpositioning in a blood vessel adjacent to an aneurysm for causingthrombosis of the aneurysm while maintaining substantially normal flowthrough the blood vessel, said device comprising:

a single elastic filament configurable between:

-   -   (i) an elongated, substantially linear configuration, whereby to        facilitate movement along a blood vessel; and    -   (ii) a longitudinally-contracted, substantially        three-dimensional configuration for lodging within the blood        vessel, said longitudinally-contracted, substantially        three-dimensional configuration providing (a) a face for        positioning adjacent the aneurysm, said face comprising a        plurality of lengths of said elastic filament in close proximity        to one another so as to restrict blood flow to the aneurysm and        thereby cause thrombosis of the aneurysm, and (b) a        substantially open frame for holding said face adjacent the        aneurysm, said substantially open frame configured so as to        maintain substantially normal flow through the blood vessel;

wherein said single elastic filament has a width which varies along itslength.

In another form of the invention, there is provided a method for makinga device for causing thrombosis of an aneurysm, wherein said devicecomprises a single elastic filament configurable between (i) anelongated, substantially linear configuration, and (ii) alongitudinally-contracted, substantially three-dimensionalconfiguration, said method comprising:

providing a filament of shape memory material;

mounting said filament of shape memory material to a fixture so thatsaid filament is transformed into said longitudinally-contracted,substantially three-dimensional configuration; and

heat treating said filament so as to produce said device in itslongitudinally-contracted, substantially three-dimensionalconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIGS. 1-3 are schematic views showing various types of aneurysms;

FIGS. 4-8 are schematic views showing a novel expandable sphericalstructure formed in accordance with the present invention, wherein theexpandable spherical structure comprises an open frame with aflow-restricting face (i.e., a closed face in this particularembodiment), and wherein the expandable spherical structure is shownbeing used to close off a lateral aneurysm in a blood vessel;

FIGS. 9-13 are schematic views showing another novel expandablespherical structure formed in accordance with the present invention,wherein the expandable spherical structure comprises an open frame witha flow-restricting face (i.e., a closed face in this particularembodiment), wherein the open frame is formed out of an absorbablematerial and the closed face is formed out of a non-absorbable material,and wherein the expandable spherical structure is shown being used toclose off a lateral aneurysm in a blood vessel;

FIG. 14-18 are schematic views showing the expandable sphericalstructure of FIGS. 4-8 being used to close off a bifurcation aneurysm;

FIG. 19-23 are schematic views showing the expandable sphericalstructure of FIGS. 9-13 being used to close off a bifurcation aneurysm;

FIG. 24 is a schematic view showing another novel expandable sphericalstructure formed in accordance with the present invention, wherein theexpandable spherical structure comprises an open frame with aflow-restricting face (i.e., a closed face in this particularembodiment), and wherein the open frame of the expandable sphericalstructure comprises a plurality of struts arranged in a rectangularpattern;

FIG. 25 is a schematic view showing another novel expandable sphericalstructure formed in accordance with the present invention, wherein theopen frame comprises a plurality of struts arranged in a hexagonalpattern;

FIG. 26 is a schematic view showing another novel expandable sphericalstructure formed in accordance with the present invention, wherein theexpandable spherical structure comprises an open frame with aflow-restricting face (i.e., a closed face in this particularembodiment), and wherein the open frame of the expandable sphericalstructure comprises a spherical spiral;

FIG. 27 is a schematic view showing another novel expandable sphericalstructure formed in accordance with the present invention, wherein theexpandable spherical structure comprises an open frame with aflow-restricting face (i.e., a closed face in this particularembodiment), and wherein the open frame of the expandable sphericalstructure comprises a spherical cage;

FIGS. 28-37 are schematic views showing other novel expandable sphericalstructures formed in accordance with the present invention, wherein theexpandable spherical structures comprise spherical cages;

FIGS. 38-43 are schematic views showing other novel expandable sphericalstructures formed in accordance with the present invention, wherein theexpandable spherical structure comprises an open frame with aflow-restricting face (i.e., a closed face in this particularembodiment), and wherein the flow-restricting face is disposed to oneside of the axis of approach;

FIGS. 44 and 45 are schematic views showing the expandable sphericalstructure of FIG. 27 being deployed with a syringe-type (e.g., an outersleeve with an internal pusher) installation tool;

FIG. 46 is a schematic view showing the expandable spherical structureof FIG. 27 being deployed with a syringe-type installation tool equippedwith a gripper mechanism;

FIGS. 47-49 are schematic views showing the expandable sphericalstructure of FIG. 27 being deployed with a syringe-type installationtool equipped with an expansion balloon;

FIGS. 50-54 are schematic views showing another novel expandablespherical structure formed in accordance with the present invention,wherein the expandable spherical structure comprises an open frame witha flow-restricting face (i.e., a face having a high strut density inthis particular embodiment), and wherein the expandable sphericalstructure is shown being used to restrict flow to a lateral aneurysm ina blood vessel;

FIGS. 55-63 are schematic views showing other expandable sphericalstructures formed in accordance with the present invention, wherein theexpandable spherical structures comprise open frames withflow-restricting faces (i.e., faces having high strut densities in theseparticular embodiments);

FIGS. 64-66 are schematic views showing the expandable sphericalstructure of FIGS. 4-8 being deployed within the interior of a lateralaneurysm so as to close off the aneurysm;

FIGS. 67-71 are schematic views showing the expandable sphericalstructure of FIGS. 9-13 being deployed within the interior of a lateralaneurysm so as to close off the aneurysm;

FIGS. 72-76 are schematic views showing the expandable sphericalstructure of FIGS. 4-8 being deployed within the interior of abifurcation aneurysm so as to close off the aneurysm;

FIGS. 77-81 are schematic views showing the expandable sphericalstructure of FIGS. 9-13 being deployed within the interior of abifurcation aneurysm so as to close off the aneurysm;

FIGS. 82 and 83 are schematic views showing an expandable sphericalstructure having stabilizing legs extending therefrom so as to form a“comet-shaped” structure, with the structure being configured torestrict flow to a lateral aneurysm in a blood vessel;

FIGS. 84-97 are schematic views showing various constructions for the“comet-shaped” structure of FIGS. 82 and 83, but with theflow-restricting face of the expandable spherical structure beingomitted in FIGS. 84-91 for clarity of viewing;

FIG. 98 is a schematic view showing another comet-shaped structure, butwith this structure being configured to restrict flow to a bifurcationaneurysm;

FIGS. 99 and 100 show an expandable spherical structure restricting flowinto a bifurcation aneurysm, where the expandable spherical structure isformed out of a “closed loop” of filament, and where the expandablespherical structure is deployed in the patient so that the face having ahigh strut density is positioned over the mouth/neck of the aneurysm inorder to restrict flow into the aneurysm;

FIGS. 101 and 102 are schematic views of an inserter which may be usedwith an expandable spherical structure formed out of a “closed loop” offilament;

FIGS. 103-107 are schematic views showing how an expandable sphericalstructure formed out of a “closed loop” of filament may be deployedusing the inserter of FIGS. 101 and 102;

FIG. 108 is a schematic view showing one preferred method for forming adevice in accordance with the present invention; and

FIGS. 109-131 are schematic views showing another preferred method forforming a device in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The Novel Expandable Spherical Structure in General

Looking now at FIGS. 4-8, there is shown a novel expandable sphericalstructure 5 formed in accordance with the present invention. Expandablespherical structure 5 is adapted for minimally-invasive, endoluminaldelivery into a blood vessel or other body lumen, for restricting flowthrough an opening in the side wall of the blood vessel or other bodylumen, and/or for reinforcing a weakness in the side wall of the bloodvessel or other body lumen, while still maintaining substantially normalflow through the blood vessel or other body lumen.

Expandable spherical structure 5 generally comprises a spherical bodycomprising an open frame 10 with a flow-restricting face 15 (i.e., aclosed face or a face having a high strut density). Preferably openframe 10 and flow-restricting face 15 together define the entireexterior shape of the spherical body, with open frame 10 making up themajority of the exterior shape of the spherical body.

In one preferred form of the invention, open frame 10 definesapproximately 90% of the exterior shape of the spherical body andflow-restricting face 15 defines approximately 10% of the exterior shapeof the spherical body. In another preferred form of the invention, openframe 10 defines approximately 80% of the exterior shape of thespherical body and flow-restricting face 15 defines approximately 20% ofthe exterior shape of the spherical body. In yet another preferred formof the invention, open frame 10 comprises approximately 70% of theexterior shape of the spherical body and flow-restricting face 15defines approximately 30% of the exterior shape of the spherical body.And in yet another preferred form of the invention, open frame 10comprises approximately 60% of the exterior shape of the spherical bodyand flow-restricting face 15 comprises approximately 40% of the exteriorshape of the spherical body.

Expandable spherical structure 5 is constructed so that it may bedeployed in a blood vessel or other body lumen, by (i) collapsing theexpandable spherical structure into a configuration of reduceddimension, (ii) moving the collapsed structure through the blood vesselor other body lumen to a therapy site, and (iii) expanding the collapsedstructure to an enlarged dimension at the therapy site, whereby tosecure the expandable spherical structure in the blood vessel or bodylumen so that its flow-restricting face 15 is presented to a side wallof the blood vessel or other body lumen, whereby to restrict flow to ananeurysm or other opening in the side wall of the blood vessel or otherbody lumen, or to otherwise reinforce a weakness in the side wall of theblood vessel or other body lumen, without significantly impeding normalflow through the blood vessel or other body lumen.

Significantly, by forming expandable spherical structure 5 in the shapeof a spherical body, the endoluminal device is readily centered on theneck of an aneurysm or other opening in a body lumen, withflow-restricting face 15 projecting into the neck of the aneurysm orother opening in a body lumen and reliably restricting flow into theaneurysm or other opening in a body lumen.

Furthermore, by forming expandable spherical structure 5 so that it canexpand at the therapy site and lodge itself in the blood vessel or otherbody lumen with its flow-restricting face 15 presented to a side wall ofthe blood vessel or other body lumen, expandable spherical structure 5is effectively self-sizing, since it can be expanded to the degreenecessary to span the blood vessel or other body lumen.

More particularly, expandable spherical structure 5 generally comprisesan open frame 10 which has a flow restricting face 15 (i.e., a closedface or a face having a high strut density) carried thereon. Open frame10 is formed so that it can assume a first, collapsed configuration ofreduced dimension (FIG. 4) so as to facilitate moving expandablespherical structure 5 endoluminally through the blood vessel or otherbody lumen to the therapy site. Open frame 10 is also formed so that itcan thereafter be re-configured to a second, expanded configuration ofenlarged dimension (FIGS. 5 and 6), whereby expandable sphericalstructure 5 can be lodged in the blood vessel or other body lumen at thetherapy site, with its flow-restricting face 15 pressed securely againsta side wall of the blood vessel or other body lumen. In this position,flow-restricting face 15 of expandable spherical structure 5 canrestrict flow to an aneurysm in the blood vessel (such as the lateralaneurysm shown in FIG. 4-8, or a bifurcation aneurysm as willhereinafter be discussed below), or restrict flow to an opening in theside wall of the blood vessel or other body lumen, or reinforce aweakness in the side wall of the blood vessel or other body lumen, etc.

Significantly, by forming the endoluminal device as an expandablespherical structure, the device can be collapsed to a reduced dimensionfor minimally-invasive, endoluminal delivery into a blood vessel orother body lumen, yet can thereafter be expanded to the requireddimension for secure lodgement at the therapy site, whereby to restrictflow to an opening in a body lumen and/or to reinforce a weakness in theside wall of the body lumen. Furthermore, by forming expandablespherical structure 5 in the shape of a spherical body, the endoluminaldevice is readily centered on the neck of an aneurysm or other openingin a body lumen, with flow-restricting face 15 projecting into the neckof the aneurysm or other opening in a body lumen and reliablyrestricting flow into the aneurysm or other opening in a body lumen. Andby forming expandable spherical structure 5 so that it can expand at thetherapy site and lodge itself in the blood vessel or other body lumenwith its flow-restricting face 15 presented to a side wall of the bloodvessel or other body lumen, expandable spherical structure 5 iseffectively self-sizing, since it expands to the degree necessary tospan the blood vessel or other body lumen. Additionally, by forming openframe 10 as an open structure, expandable spherical structure 5 can bedisposed in the blood vessel or body lumen without significantlyimpeding normal flow through the blood vessel or other body lumen (FIGS.6-8).

Expandable Open Frame 10

As noted above, (i) expandable spherical structure 5 generally comprisesa spherical body comprising an open frame 10 with a flow-restrictingface 15 (i.e., a closed face or a face having a high strut density);(ii) open frame 10 and flow-restricting face 15 together preferablydefine the entire exterior shape of the spherical body, with open frame10 making up the majority of the exterior shape of the spherical body;(iii) open frame 10 is capable of being collapsed in dimension for easydelivery of expandable spherical structure 5 to the therapy site andthereafter expanded in dimension at the therapy site so as to holdflow-restricting face 15 against a side wall of a blood vessel or otherbody lumen; and (iv) open frame 10 is configured so that it does notsignificantly impede normal flow through the blood vessel or lumenwithin which it is deployed.

To this end, open frame 10 is preferably formed with an expandable strutconstruction, so that it can (i) first assume a configuration of reduceddimension, so that expandable spherical body 5 can move easily throughthe body to the therapy site, and (ii) thereafter assume a configurationof expanded dimension, so that it can be securely retained at thedesired location in the blood vessel or other body lumen and pressflow-restricting face 15 securely against the side wall of the bloodvessel or body lumen, whereby to restrict flow to an aneurysm or otheropening in the blood vessel or other body lumen, or to otherwisereinforce the side wall of the blood vessel or other body lumen. And byforming open frame 10 with an expandable strut construction, open frame10 is effectively self-sizing, since it expands to the degree necessaryto span the blood vessel or other body lumen.

Significantly, by forming open frame 10 with an expandable strutconstruction, open frame 10 does not significantly impede normal flowthrough the blood vessel or other body lumen when open frame 10 is inits expanded configuration within the blood vessel or other body lumen.

Thus, for example, in the configuration shown in FIGS. 4-8, open frame10 comprises a plurality of struts arranged in a polygonalconfiguration, with the struts being sized so that the struts presentminimal obstruction to normal flow through the lumen.

In one preferred construction, open frame 10 may be formed out of ashape memory alloy (SMA) such as Nitinol, and a temperature transitionmay be used to change the configuration of open frame 10. By way ofexample but not limitation, open frame 10 can be formed so that when itis cooled to a temperature below body temperature, the open frameassumes a collapsed configuration (FIG. 4), and when it is thereafterwarmed to body temperature, the open frame assumes an expandedconfiguration (FIG. 6). If desired, open frame 10 can be warmed to bodytemperature simply by deploying expandable spherical structure 5 in thebody. Alternatively, an electrical current may be applied to open frame10 so as to heat open frame 10 to its expansion temperature, e.g., viaresistance heating. Or, a warm or cold saline solution can be flushedthrough open frame 10 so as to appropriately modulate the temperature ofthe open frame, whereby to cause the open frame to assume a desiredconfiguration.

Alternatively, open frame 10 can be formed out of a resilient materialwhich can be forcibly compressed into a collapsed configuration,restrained in this collapsed configuration, and thereafter released sothat it elastically returns to its expanded configuration. By way ofexample but not limitation, in this form of the invention, expandablespherical structure 5 might be compressed into a configuration of areduced dimension, restrained within a sleeve, delivered to the therapysite within the sleeve, and then released from the sleeve so that itelastically returns to an expanded configuration at the therapy site,whereby to lodge itself in the blood vessel or other body lumen, withits flow-restricting face pressed against the side wall of the bloodvessel or other body lumen. By way of further example but notlimitation, open frame 10 can be formed out of a shape memory alloy(SMA) engineered to form stress-induced martensite (SIM) and therebyexhibit superelastic properties, whereby to permit large shapedeformations with elastic return. By way of still further example butnot limitation, open frame 10 can be formed out of a suitable polymerwhich exhibits the desired elastic properties.

In another preferred form of the present invention, open frame 10 isformed with a structure which can be collapsed for delivery to thedeployment site and thereafter enlarged to an expanded configurationthrough the use of an expansion device, e.g., an internal balloon, wherethe balloon is inflated at the therapy site so as to reconfigure openframe 10 to an expanded condition. This arrangement can be advantageous,since it does not require the open frame to rely on temperaturetransition or elasticity to expand to its fully expanded configuration(or to any desired expanded configuration less than its fully expandedconfiguration). Thus, a wide range of well known biocompatible materials(e.g., medical grade stainless steel) may be used to form open frame 10.

Flow-Restricting Face 15

Flow-restricting face 15 is carried by (e.g., mounted on, formedintegral with, or otherwise connected to) open frame 10 so thatflow-restricting face 15 can be pressed securely against the side wallof the blood vessel or other body lumen within which expandablespherical structure 5 is deployed.

Flow-restricting face 15 may comprise a closed face, in the sense thatit comprises a substantially complete surface or barrier which iscapable of closing off an aneurysm or other opening in side wall of ablood vessel or other body lumen, and/or for reinforcing a weakness inthe side wall of the blood vessel or other body lumen. See FIGS. 4-8,where flow-restricting face 15 is depicted as a closed face.

Alternatively, and as will be discussed in detail below,flow-restricting face 15 may comprise a face having a high strut densitywhich is capable of restricting flow to an aneurysm or other opening ina side wall of a blood vessel or other body lumen, and/or forreinforcing a weakness in the side wall of the blood vessel or otherbody lumen. In this case, flow-restricting face 15 may not constitute asubstantially complete surface, or flow-restricting face 15 may notconstitute a substantially fluid-impervious surface, butflow-restricting face 15 will have a strut density sufficiently high torestrict flow through that face, e.g., so as to cause an aneurysm tothrombose.

Flow-restricting face 15 may be formed so as to be substantially rigidor it may be formed so as to be flexible.

Flow-restricting face 15 preferably has the convex configuration shownin FIGS. 4-8, so that it can form a regular portion of the sphericalbody of expandable structure 5. However it should be appreciated thatflow-restricting face 15 may also be formed with a planar configuration,or some other configuration, if desired.

Use of Absorbable Materials

If desired, expandable spherical structure 5 can have some or all of itselements formed out of an absorbable material, so that some or all ofthe elements are removed from the therapy site after some period of timehas elapsed.

By way of example but not limitation, open frame 10 can be formed out ofan absorbable material, and flow-restricting face 15 can be formed outof a non-absorbable material, so that only flow-restricting face 15 isretained at the therapy site after some period of time has passed. SeeFIGS. 9-13. This type of construction can be advantageous whereflow-restricting face 15 integrates into the side wall of the bloodvessel or other body lumen after some period of time has elapsed, sothat a supporting frame is no longer necessary to hold flow-restrictingface 15 in position against the side wall of the blood vessel or otherbody lumen.

It is also possible for the entire expandable spherical structure 5 tobe formed out of absorbable material(s), i.e., with both open frame 10and flow-restricting face 15 being formed out of absorbable materials.This type of construction can be advantageous where flow-restrictingface 15 only needs to be held against the side wall of the blood vesselor other body lumen for a limited period of time, e.g., until aneurysmthrombosis/scarring is complete, or to reinforce the side wall of theblood vessel or other body lumen while healing occurs, etc.

It should also be appreciated that, where both open frame 10 andflow-restricting face 15 are absorbable, they may be engineered so as tohave different absorption rates, so that they are removed from thetherapy site at different times. This may be done by making the variouselements out of different materials, or by making the various elementsout of different blends of the same materials, etc.

Application to Different Types of Aneurysms

As noted above, expandable spherical structure 5 can be used to restrictflow to various types of aneurysms.

Thus, for example, FIGS. 4-8 and 9-13 show expandable sphericalstructure 5 being used to restrict flow to a lateral aneurysm (i.e., inthese particular embodiments, to close off the lateral aneurysm).

However, it should also be appreciated that expandable sphericalstructure 5 may be used to restrict flow to a bifurcation aneurysm aswell. Thus, for example, FIG. 14-18 show the expandable sphericalstructure 5 of FIG. 4-8 being used restrict flow to a bifurcationaneurysm, and FIG. 19-23 show the expandable spherical structure 5 ofFIG. 9-13 being used to restrict flow to a bifurcation aneurysm (i.e.,in these particular embodiments, to close off the bifurcation aneurysm).In this respect it should be appreciated that the spherical shape ofexpandable spherical structure 5 is particularly well suited for use intreating bifurcation aneurysms, since it may be seated securely at thebifurcation, pressing flow-restricting face 15 securely against thebifurcation aneurysm, while still allowing blood to flow substantiallyunobstructed through the blood vessels.

It is also anticipated that expandable spherical structure 5 may be usedto restrict flow to other types of aneurysms as well, e.g., certainforms of fusiform aneurysms. Where expandable spherical structure 5 isto be used to restrict flow to a fusiform aneurysm, flow-restrictingface 15 may comprise a significantly enlarged surface area, orflow-restricting face 15 may comprise two or more separated segmentsdisposed about the lateral portions of open frame 10, etc.

Structure of Open Frame 10

It should be appreciated that open frame 10 can be formed with a varietyof different configurations without departing from the scope of thepresent invention.

In one form of the invention, open frame 10 may be formed out of aplurality of struts arranged in a polygonal array. See, for example,FIGS. 4-8, 9-13, 14-18 and 19-23, where open frame 10 is shown formedout of a plurality of struts arranged as triangular polygons. See alsoFIG. 24, where open frame 10 is formed out of a plurality of strutsarranged as rectangular polygons, and FIG. 25, where open frame 10 isformed out of a plurality of struts arranged as hexagons.

It is also possible to form open frame 10 with a non-polygonalstructure.

Thus, for example, open frame 10 may be formed with a spherical spiralstructure, e.g., such as is shown in FIG. 26, where a spiral strut formsthe open frame 10.

FIG. 27 shows an open frame 10 having a spherical cage structure. Moreparticularly, in this construction, open frame 10 comprises a pluralityof axially-aligned struts 20 which extend between flow-restricting face15 and an annular ring 25. Struts 20 preferably bow outwardly when openframe 10 is in its expanded configuration, but may be bent inwardly(e.g., to a straight or inwardly-bowed configuration) or otherwisedeformed so as to permit open frame 10 to assume a reducedconfiguration. By way of example but not limitation, struts 20 may bebent inwardly (e.g., so as to extend substantially parallel to oneanother) when open frame 10 is in its reduced configuration.

FIGS. 28-37 show other spherical cage constructions wherein variousstruts 20 form open frame 10.

It will be appreciated that, with the construction shown in FIG. 27,flow-restricting face 15 sits at one end of the plurality ofaxially-aligned struts 20 and annular ring 25 sits at the opposing endof the plurality of axially-aligned struts 20. Since struts 20 areintended to be bowed inwardly so that the expandable spherical structurecan assume a reduced configuration, the spherical cage structure of FIG.27 is generally intended to be delivered axially, with flow-restrictingface 15 leading. Thus, this construction is particularly well suited foruse with bifurcation aneurysms, where the neck of the aneurysm istypically axially-aligned with the direction of approach (see, forexample, FIGS. 14-18 and 19-23). Accordingly, where the spherical cagestructure is intended to be used with lateral aneurysms, it may bedesirable to use the spherical cage configuration shown in FIG. 38,where flow-restricting face 15 is disposed to one side of the axis ofapproach, i.e., to one side of the axis 27 shown in FIG. 38. In otherwords, where the spherical cage structure is intended to be used with abifurcation aneurysm, flow-restricting face 15 is intended to be alignedwith the axis of approach, and where the spherical cage structure isintended to be used with a lateral aneurysm, flow-restricting face 15 isintended to be disposed to one side of the axis of approach. In thisway, expandable spherical structure 5 can be endoluminally advanced tothe therapy site and flow-restricting face 15 properly positionedrelative to the anatomy.

FIGS. 39-43 show other spherical cage constructions wherein variousstruts 20 form open frame 10 and flow-restricting face 15 is disposed toone side of the axis of approach.

Installation Tools

Various installation tools may be provided to deploy expandablespherical structure 5 within a blood vessel or other body lumen.

Thus, for example, in FIG. 44, there is shown a syringe-type (e.g., anouter sleeve with an internal pusher) installation tool 100 fordeploying the expandable spherical structure 5 shown in FIG. 45.Installation tool 100 generally comprises a hollow sleeve 105 having alumen 110 therein, and a pusher 115 slidably disposed within lumen 110.Lumen 110 is sized so that it can accommodate expandable sphericalstructure 5 when the expandable spherical structure is in its reducedconfiguration (FIG. 44), but not when it is in its enlargedconfiguration (FIG. 45). As a result of this construction, expandablespherical structure 5 may be positioned within lumen 110 (distal topusher 115) when expandable spherical structure 5 is in its reducedconfiguration, advanced to the therapy site while within sleeve 105, andthen installed at the therapy site by advancing pusher 115 so thatexpandable spherical structure 5 is ejected from the interior of sleeve105. Once expandable spherical structure 5 has been ejected from sleeve105, expandable spherical structure 5 can return to an expandedconfiguration (FIG. 45) so as to be securely engaged in the blood vesselor other body lumen in the manner previously described, withflow-restricting face 15 pressed against a side wall of the blood vesselor other body lumen. It will be appreciated that the syringe-typeinstallation tool 100 is particularly advantageous where expandablespherical structure 5 is elastically deformable, such that sleeve 105can serve to mechanically restrain the expandable spherical structure inits reduced configuration while the expandable spherical structure iswithin sleeve 105, and release that mechanical constraint when theexpandable spherical structure is ejected from sleeve 105.

As noted above, expandable spherical structure 5 of FIGS. 27, 44 and 45is well suited for use with bifurcation aneurysms, where the neck of theaneurysm is typically axially-aligned with the direction of approach(see, for example, FIGS. 14-18 and 19-23). Where the spherical cagestructure is intended to be used with lateral aneurysms, it may bedesirable to use the spherical cage configuration shown in FIG. 38,where flow-restricting face 15 is disposed to one side of the axis ofapproach.

If desired, installation tool 100 can be provided with a grippermechanism to releasably secure expandable spherical structure 5 toinstallation tool 100, e.g., so as to releasably secure expandablespherical structure 5 to installation tool 100 until after expandablespherical structure 5 has been advanced to the therapy site and hasreturned to its enlarged configuration, so that it is ready to be leftat the therapy site. This gripper mechanism ensures complete control ofexpandable spherical structure 5 as it is moved out of the installationtool and erected within the body, and also facilitates more precisepositioning (e.g., with proper rotation, etc.) of the expandablestructure against the side wall of the body lumen.

More particularly, and looking now at FIG. 46, installation tool 100 maybe provided with a plurality of spring grippers 125. Spring grippers 125are disposed within lumen 110 of sleeve 105, exterior to pusher 115.Each spring gripper 125 is formed so that when a bowed portion 130 ofthe spring gripper is restrained within lumen 110, a hook portion 135 ofthat spring gripper holds annular ring 25 of expandable sphericalstructure 5 to the distal end of pusher 115. However, when pusher 115 isadvanced to the point where bowed portion 130 of spring gripper 125 isno longer restrained within lumen 110, hook portion 135 of springgripper 125 moves outboard so as to release annular ring 25 ofexpandable spherical structure 5 from the distal end of pusher 115. Thusit will be seen that spring grippers may be used to releasably secureexpandable spherical structure 5 to installation tool 100 until afterthe expandable spherical structure has been advanced out of the distalend of the installation tool and returned to its enlarged configuration.This arrangement can provide the clinician with increased control asexpandable spherical structure 5 is deployed within the blood vessel.

As noted above, expandable spherical structure 5 of FIGS. 27 and 44-46is well suited for use with bifurcation aneurysms, where the neck of theaneurysm is typically axially-aligned with the direction of approach(see, for example, FIGS. 14-18 and 19-23). Where the spherical cagestructure is intended to be used with lateral aneurysms, it may bedesirable to use the spherical cage configuration shown in FIG. 38,where closed face 15 is disposed to one side of the axis of approach.

If desired, installation tool 100 can be provided with an expansionballoon for expanding the expandable spherical structure from itsreduced configuration to its enlarged configuration. More particularly,and looking now at FIGS. 47-49, installation tool 100 may be providedwith sleeve 105 and pusher 115 as discussed above. In addition,installation tool 100 may be provided with an expansion balloon 140.Expansion balloon 140 is supported on an inflation rod 145 which ismovably disposed within pusher 115. Expansion balloon 140 is (in itsdeflated condition) disposed internal to open frame 10 of expandablespherical structure 5. As a result of this construction, installationtool 100 may receive expandable spherical structure 5 while theexpandable spherical structure is in its reduced configuration, carrythe expandable spherical structure to the desired therapy site, positionthe expandable spherical structure at the desired location, and thenexpand expansion balloon 140 so as to open the expandable sphericalstructure to its enlarged configuration. Expansion balloon 140 may thenbe deflated and withdrawn from the interior of expandable sphericalstructure 5. It will be appreciated that providing installation tool 100with an expansion balloon may be advantageous where expandable sphericalstructure 5 does not self-erect within the body lumen.

Expandable Spherical Structure Having a Flow-Restricting Face Formedwith a High Strut Density

In FIGS. 1-50, flow-restricting face 15 of expandable sphericalstructure 5 is depicted as a closed face, in the sense thatflow-restricting face 15 comprises a substantially complete surface orbarrier which is capable of closing off (and/or very significantlyreducing flow to) an aneurysm or other opening in the side wall of ablood vessel or other body lumen, and/or for reinforcing a weakness inthe side wall of the blood vessel or other body lumen. However, itshould be appreciated that for many applications, flow-restricting face15 need not comprise a substantially complete surface or barrier, i.e.,flow-restricting face 15 may be formed with a face having a sufficientlyhigh strut density to form an effectively closed face or to otherwiseachieve a desired purpose. Thus, for example, in FIGS. 50-54, there isshown an expandable spherical structure 5 comprising an open frame 10having a flow-restricting face 15 formed with a high strut density suchthat blood flow to the aneurysm will be restricted and the aneurysm willthrombose. In this circumstance, flow-restricting face 15 may beconsidered to be effectively closed. Furthermore, where flow-restrictingface 15 is being used to reinforce a weakness in a side wall (as opposedto being used to restrict flow to an opening in a side wall), closedface 15 may have a somewhat lower strut density, since it does not needto significantly restrict the flow of a fluid.

FIGS. 55-63 show other expandable spherical structures 5 whereinflow-restricting face 15 is formed with a sufficiently high strutdensity to achieve a desired purpose. In this respect it will beappreciated that, as used herein, the term strut is intended to meansubstantially any element spaced from an adjacent element or in contactwith an adjacent element. Thus, where flow-restricting face 15 is formedby a face having a high strut density, the struts may be in the form ofa screen, a mesh, a lattice, a series of parallel or concentricinterlaced or otherwise patterned struts, etc.

It should also be appreciated that it is possible to form the entireexpandable spherical structure 5 out of a single superelastic wire,e.g., a shape memory alloy constructed so as to form stress-inducedmartensite at body temperatures. By way of example but not limitation,an appropriately blended and treated Nitinol wire may be used. In thisform of the invention, the expandable spherical structure 5 can be (i)deformed into a collapsed configuration wherein a single path of thewire is constrained within a restraining cannula, and (ii) thereafterreformed in situ by simply pushing the wire out of the distal end of therestraining cannula, whereupon expandable spherical structure 5 reformsin the blood vessel or other body lumen. This form of the invention isparticularly well suited to constructions where flow-restricting face 15is formed with a single, patterned strut arranged to have a high strutdensity, e.g., with a strut density sufficiently high to restrict flowto the mouth of an aneurysm, and/or a strut density sufficiently high toreinforce the side wall of a blood vessel or other body lumen, and/or astrut density sufficiently high to achieve some other desired purpose.See, for example, FIGS. 59-63, which show flow-restricting face 15formed out of a single, patterned strut, where the strut pattern maycomprise one or more of a variety of configurations, e.g., with parallelpaths, concentric paths, switchback paths, serpentine paths, etc.

Utilizing the Expandable Spherical Structure in Conjunction withThrombosis-Inducing Coils

As noted above, conventional minimally-invasive techniques for treatingbrain aneurysms generally involve depositing thrombosis-inducing coilswithin the dome of the aneurysm. If desired, the expandable sphericalstructure 5 of the present invention may be used in conjunction withthrombosis-inducing coils, i.e., the thrombosis-inducing coils may bedeposited within the dome of an aneurysm after positioning theexpandable spherical structure against the mouth of the aneurysm so asto restrict flow into the aneurysm, i.e., by introducing thethrombosis-inducing coils through the face having a high strut densityand into the dome of the aneurysm. Alternatively, thethrombosis-inducing coils may be deposited within the dome of theaneurysm before positioning the expandable spherical structure againstthe mouth of the aneurysm so as to restrict flow into the aneurysm.Significantly, it is believed that this approach will both facilitatethrombosis formation and also prevent coil migration out of theaneurysm.

Deploying the Expandable Spherical Structure within an Aneurysm

It should also be appreciated that expandable spherical structure 5 maybe deployed within the body of an aneurysm so that its flow-restrictingface 15 confronts the lumen, rather than being within the lumen so thatits flow-restricting face confronts the body of the aneurysm. See, forexample, FIGS. 64-66, which show the expandable spherical structure 5 ofFIGS. 4-8 deployed within the body of the aneurysm. See also, forexample, FIGS. 67-71, which show the expandable spherical structure 5 ofFIGS. 9-13 being disposed within the body of the aneurysm.

Again, the expandable spherical structure 5 may be positioned within theinterior of a lateral aneurysm (FIGS. 64-66 and 67-71) or it may bedisposed within a bifurcated aneurysm (FIGS. 72-76 and 77-81).

Expandable Spherical Structure with Stabilizing Legs Comet-ShapedStructure

It is also possible to provide expandable spherical structure 5 withstabilizing legs. Such a construction may be adapted for use with bothlateral aneurysms and with bifurcation aneurysms.

More particularly, and looking now at FIGS. 82 and 83, there is shown anexpandable spherical structure 5 which comprises an open frame 10 with aflow-restricting face 15. Extending out of open frame 10 are one or morestabilizing legs 30. Stabilizing legs 30 are formed so that, whenflow-restricting face 15 is positioned against the side wall of a bloodvessel or other body lumen, stabilizing legs 30 extend endoluminallythrough the blood vessel or other body lumen. Thus it will beappreciated that the expandable spherical structure 5 shown in FIGS. 82and 83 is generally intended to be used with a lateral aneurysm, sincethe center axis 35 of stabilizing legs 30 is set at a right angle to thecenter axis 40 of flow-restricting face 15 (see FIG. 83).

Preferably, and as seen in FIGS. 82 and 83, stabilizing legs 30 togetherform a somewhat cone-shaped structure, so that the overall shape of openframe 10 (with flow-restricting face 15) and stabilizing legs 30 is agenerally comet-shaped structure.

As seen in FIG. 84, this comet-shaped structure may be compressed withina containment sheath 200, with stabilizing legs 30 leading and with openframe 10 (with flow-restricting face 15) trailing, and with a pushcatheter 205 and tension wire 210 engaging open frame 10 of expandablespherical structure 5. At the aneurysm site, push catheter 205 ejectsthe comet-shaped structure, “legs first”, so that closed face 15restricts access to the mouth of the aneurysm while stabilizing legs 30help maintain the position of open frame 10 (and flow-restricting face15) within the blood vessel. This deployment procedure is preferablyconducted over a guidewire 215.

If the comet-shaped structure subsequently needs to be repositioned orremoved from a deployment site, tension wire 210 may be used to pull thecomet-shaped structure retrograde, e.g., within the blood vessel or allthe way back into containment sheath 200. To this end, and looking nowat FIGS. 85-87, open frame 10 of expandable spherical structure 5 maycomprise a proximal end ring 220, and tension wire 210 may comprise anexpandable head 225 adapted to extend through proximal end ring 220 andthen expand, whereupon the comet-shaped structure may be movedretrograde. Alternatively, open frame 10 of expandable sphericalstructure 5 may comprise an apex 230 of converging wires which can begripped by a J-hook 235 formed on the distal end of tension wire 210(FIG. 88) or by C-fingers 240 formed on the distal end of tension wire210 (FIG. 89).

If desired, and looking now at FIGS. 85-87, the distal ends ofstabilizing legs 30 may be turned into eyelets 245, so as to minimizetrauma (during both placement and repositioning) to the side wall of thebody lumen (e.g., blood vessel) in which they are disposed.

It will be appreciated that, where flow-restricting face 15 covers onlya portion of the circumference of open frame 10, it can be important forthe clinician to ensure the rotational disposition of the comet-shapedstructure so that flow-restricting face 15 is properly aligned with themouth of the lateral aneurysm. For this reason, and looking now at FIG.90, push catheter 205 may include a plurality of slits 250 on its distalend which receive the constituent wires of open frame 10, whereby topermit the clinician to adjust the rotational disposition of thecomet-shaped structure (and hence the rotational disposition offlow-restricting face 15 of open frame 10). Alternatively, and lookingnow at FIG. 91, push catheter 205 may be formed with an obround shape(or any other appropriate non-circular shape) so as to permit theclinician to specify the rotational disposition of the comet-shapedstructure (and hence the rotational disposition of flow-restricting face15 of open frame 10).

Looking now at FIGS. 92 and 93, flow-restricting face 15 of open frame10 can be formed by wrapping a membrane 255 over the wire skeletonmaking up open frame 10 and securing it in position. Thus, FIGS. 94 and95 show membrane 255 covering only a portion of the circumference offrame 10, and FIGS. 96 and 97 show membrane 255 covering the completecircumference of frame 10.

In the foregoing description, the expandable spherical structure 5 ofFIGS. 82 and 83 is discussed in the context of a “legs-first” deploymentinto the blood vessel or other body lumen. However, it should also beappreciated that the expandable spherical structure 5 of FIGS. 82 and 83may be deployed “head-first” into the blood vessel or other body lumen(i.e., with stabilizing legs 30 trailing open frame 10).

Looking next at FIG. 98, it is also possible to provide a comet-shapedstructure which can be used with a bifurcation aneurysm. Moreparticularly, in this form of the invention, expandable sphericalstructure 5 is formed so that center axis 40 of flow-restricting face 15is aligned with center axis 35 of stabilizing legs 30. It will beappreciated that where the comet-shaped structure is to be used with totreat a bifurcation aneurysm, it is generally desirable that the “head”of the comet (which comprises flow-restricting face 15) be ejected outof containment sheath 200 first, with stabilizing legs 30 trailing,whereby to easily place flow-restricting face 15 against the mouth ofthe aneurysm.

Expandable Spherical Structure Formed Out of a “Closed Loop” of Filament

In the preceding description, expandable spherical structure 5 isdescribed as comprising an open frame 10 having a flow-restricting face15 carried thereon. More particularly, in some embodiments of theinvention, flow-restricting face 15 comprises a substantially completesurface or barrier. See, for example, FIGS. 4-49. However, in otherembodiments of the invention, flow-restricting face 15 need not comprisea substantially complete surface or barrier, i.e., flow-restricting face15 may be formed with a face having a sufficiently high strut density toform an effectively closed face or to otherwise achieve a desiredpurpose. Thus, for example, in FIGS. 50-58, there is shown an expandablespherical structure 5 comprising an open frame 10 having aflow-restricting face 15 formed with a high strut density such thatblood flow to the aneurysm will be restricted and the aneurysm willthrombose. In this circumstance, flow-restricting face 15 may beconsidered to be effectively closed, in the sense that flow-restrictingface 15 is sufficiently closed to decrease flow velocity in the aneurysmand result in thrombosis within the aneurysm. Furthermore, whereflow-restricting face 15 is being used to reinforce a weakness in a sidewall (as opposed to being used to close off an opening in a side wall orto otherwise restrict flow through that opening), flow-restricting face15 may have a somewhat lower strut density. In any case, however,flow-restricting face 15 will still have a significantly higher strutdensity than that of open frame 10.

In the preceding description, it was noted that it is possible to formthe entire expandable spherical structure 5 out of a single superelasticwire, e.g., a shape-memory alloy constructed so as to formstress-induced martensite at body temperatures. It was also noted that,in this form of the invention, the expandable spherical structure 5 canbe (i) deformed into a collapsed configuration wherein a single path ofthe wire is constrained within a constraining cannula, and (ii)thereafter reformed in situ by simply pushing the wire out of the distalend of the restraining cannula, whereupon expandable spherical structure5 reforms in the blood vessel or other body lumen. It was further notedthat this form of the invention is particularly well suited toconstructions wherein closed face 15 is formed with a single, patternedstrut arranged to have a high strut density, e.g., with a strut densitysufficiently high to restrict the flow of blood through the mouth of ananeurysm (i.e., to cause thrombosis of the aneurysm), and/or a strutdensity sufficiently high to reinforce the side wall of a blood vesselor other body lumen, and/or a strut density sufficiently high to achievesome other desired purpose. Again, however, flow-restricting face 15will still have a significantly higher strut density than that of openframe 10. See, for example, FIGS. 59-63, which show flow-restrictingface 15 formed out of a single, patterned strut, where the strut patternmay comprise one or more of a variety of configurations, e.g., withparallel paths, concentric paths, switchback patterns, serpentine paths,etc.

In accordance with the present invention, there is now disclosed afurther construction wherein expandable spherical structure 5 is formedout of a closed loop of filament such as highly flexible wire (e.g.,Nitinol) which has been worked (e.g., on a mandrel) so that its numerousturns approximate the shape of a sphere or ellipsoid when the loop is inits relaxed condition. One face of the sphere (i.e., flow-restrictingface 15) has a higher turn density than the remainder of the sphere(i.e., open frame 10) so that the high density face can restrict bloodflow while the remainder of the sphere easily passes blood flow. Theclosed loop of filament may be transformed from its spherical shape intoanother shape by applying physical forces (e.g., tension) to the closedloop of filament. Thus, the closed loop of filament may be transformedfrom its three-dimensional substantially spherical configuration into asubstantially two-dimensional “elongated loop” configuration (e.g., byapplying two opposing forces to the interior of the loop) in order thatthe closed loop of filament may be advanced endoluminally to the site ofan aneurysm. Once at the site of the aneurysm, the tension on theelongated loop may be released so that the closed loop of filamentreturns to its spherical shape, whereby to lodge in the blood vesselwith the high density face (i.e., flow-restricting face 15) divertingthe flow of blood away from the aneurysm (i.e., to cause thrombosiswithin the aneurysm) while the remainder of the sphere (i.e., open frame10) easily passes blood flowing through the parent vessel. If the spheresubsequently needs to be re-positioned within the blood vessel, thetension is re-applied to the sphere so as to transform it part or allthe way back to its elongated loop configuration, the position of thedevice is adjusted, and then the foregoing process repeated so as to setthe sphere at a new position within the blood vessel. Furthermore, ifthe sphere needs to be removed from the blood vessel, the tension isre-applied to the sphere so as to transform it back to its elongatedloop configuration, and then the loop is removed from the patient.Significantly, this construction has the advantages of (i) ease ofpositioning, (ii) reliably maintaining its deployed position within thevessel, (iii) ease of re-positioning within the body, and (iv) wherenecessary, removal from the body.

By way of example but not limitation, FIG. 63 shows a expandablespherical structure 5 which is formed out of a closed loop of highlyflexible wire. As can be seen in FIG. 63, expandable spherical structure5 approximates the shape of a sphere or ellipsoid when the loop is inits relaxed condition. FIG. 63 shows expandable spherical structure 5being used to restrict blood flow to a lateral aneurysm. FIGS. 99 and100 show expandable spherical structure 5 being used to restrict bloodflow to a bifurcation aneurysm.

FIGS. 101 and 102 shows an inserter 300 which can be used to reconfiguresuch a “closed loop” expandable spherical structure 5 from its relaxedspherical (or elliptical) configuration into an elongated loopconfiguration. To this end, inserter 300 preferably comprises an innercatheter 305 which includes a bifurcated distal end 310 which can seat asegment of the closed loop. Inserter 300 preferably also comprises anouter catheter 315 which includes a mount 320 which can seat anothersegment of the closed loop.

In use, and as shown in FIGS. 103-107, inserter 300 is set so that itsouter catheter 315 is adjacent to bifurcated distal end 310, and then asegment of the closed loop expandable spherical structure 5 is seated inbifurcated distal end 310 and another segment of the closed loopexpandable spherical structure is seated in mount 320 of outer catheter315. Then outer catheter 315 is moved proximally so that the closed loopexpandable spherical structure 5 is reconfigured from its relaxedspherical (or elliptical) configuration into an elongated loopconfiguration, e.g., in the manner of a tensioned elastic band. With theclosed loop expandable spherical structure 5 held in this elongatedcondition on inserter 300, a transport sheath 325 is (optionally) beplaced over the assembly. Inserter 300 (with its passenger closed loopexpandable spherical structure 5 and with its overlying transport sheath325) is moved through the patient's anatomy until spherical structure 5is located at the surgical site. Then transport sheath 325 is removedand outer catheter 315 is moved distally on inner catheter 305. As outercatheter 315 is moved distally on inner catheter 305, tension onexpandable spherical structure 5 is released so that expandablespherical structure 5 can re-assume its spherical or elliptical shapeand engage the adjacent anatomy. Then expandable spherical structure 5is disengaged from inserter 300, and inserter 300 is removed from thesurgical site.

If, after deployment, the closed loop expandable spherical structureneeds to be re-positioned within the blood vessel, inserter 300 is usedto re-apply tension to the sphere so as to transform the sphere part orall the way back to its loop configuration, the position of the deviceis adjusted, and then the foregoing process is repeated so as to set thesphere at a new position within the blood vessel.

Furthermore, if, after deployment, the closed loop expandable sphericalstructure 5 needs to be removed from the blood vessel, inserter 300 isused to re-apply tension to the sphere so as to transform it back to itsloop configuration, and then the loop is removed from the patient.

Significantly, this construction has the advantages of (i) ease ofpositioning, (ii) reliably maintaining its deployed position within thevessel, (iii) ease of re-positioning within the body, and (iv) wherenecessary, removal from the body.

Terminology

In the foregoing disclosure, expandable spherical structure 5 isdescribed as comprising a spherical body. In this regard, it should beappreciated that the term “spherical” is intended to mean a truespherical shape, and/or a substantially spherical shape, and/or a nearspherical shape (including but not limited to an ellipsoid shape or asubstantially ellipsoid shape or a near ellipsoid shape), and/or aneffectively spherical shape, and/or a generally spherical shape, and/ora polyhedron which approximates a sphere, and/or a shape whichapproximates a sphere, and/or a structure comprising a substantialportion of any of the foregoing, and/or a structure comprising acombination of any of the foregoing, etc.

Thus, for example, expandable spherical structure 5 may include a firstsection that constitutes a portion of a sphere and a second sectionwhich roughly approximates the remaining portion of a sphere.

Method for Manufacturing the Novel Device from a Single Elastic Filament

In the foregoing disclosure, there is disclosed a novel device for,among other things, positioning in a blood vessel (or vessels) adjacentto the mouth of an aneurysm and for causing thrombosis of the aneurysmby restricting blood flow to the aneurysm while maintainingsubstantially normal blood flow through the blood vessel (or vessels)which receive(s) the device, wherein the device comprises a singleelastic filament configurable between: (i) a longitudinally-expanded,substantially linear configuration, whereby to facilitate movement ofthe device along the vascular system of the patient to the site of theaneurysm; and (ii) a longitudinally-contracted, substantiallythree-dimensional configuration for lodging within the central lumen ofthe blood vessel (or vessels) adjacent to the mouth of the aneurysm, thelongitudinally-contracted, substantially three-dimensional configurationproviding (a) a flow-restricting face for positioning at the mouth ofthe aneurysm, the flow-restricting face comprising a plurality oflengths of the single elastic filament disposed in close proximity toone another so as to significantly restrict blood flow to the aneurysmand thereby cause thrombosis of the aneurysm, and (b) a substantiallyopen frame for holding the flow-restricting face adjacent to the mouthof the aneurysm, the substantially open frame being configured so as tomaintain substantially normal blood flow through the central lumen ofthe blood vessel (or vessels) which receive(s) the device.

In one preferred form of the present invention, the novel device isformed out of a single elastic filament having distinct first and secondends, and the longitudinally-expanded, substantially linearconfiguration is formed by disposing the first and second endsoppositely away from one another. In another preferred form of thepresent invention, the device is formed out of a single elastic filamenthaving its first and second ends unified with one another (e.g., bywelding, by banding, etc.) so as to effectively form a continuous,closed loop of elastic filament, and the longitudinally-expanded,substantially linear configuration is formed by disposing thecontinuous, closed loop of elastic filament so that it essentiallyconsists of two parallel lengths of the single elastic filament.

And in one preferred form of the present invention, thelongitudinally-contracted, substantially three-dimensional configurationis substantially spherical, or substantially ellipsoid, or some otherthree-dimensional shape appropriate for holding the flow-restrictingface of the device against the mouth of the aneurysm while maintainingsubstantially normal blood flow through the central lumen of the bloodvessel (or vessels) which receive(s) the device.

And in one preferred form of the present invention, the single elasticfilament comprises a shape memory material, e.g., Nitinol, with theelastic filament transforming between its longitudinally-expanded,substantially linear configuration and its longitudinally-contracted,substantially three-dimensional configuration by temperature transitionor by superelasticity.

And in one preferred form of the present invention, the shape memorymaterial may comprise an appropriate nickel titanium alloy (e.g.,Nitinol), an appropriate copper-based alloy (e.g., Cu—Zn—Al, Cu—Al—Ni,Cu—Al—Mn, Cu—Al—Be, etc.), and an appropriate iron-based alloy (e.g.,Fe—Mn—Si, Fe—Cr—Ni—Mn—Si—Co, Fe—Ni—Mn, Fe—Ni—C, Fe—Pt, Fe—Pd, etc.),etc. Additionally, the shape memory material may comprise a shape memorypolymer.

In order for a shape memory material to be capable of automaticallytransforming between a “first shape” and a “second shape” by temperaturetransition or by superelasticity, it is necessary to first process theshape memory material in a particular manner. More particularly, theshape memory material is initially formed with the “first shape”, thenit is mechanically transformed to the desired “second shape” and then,while mechanically held in the desired “second shape” (e.g., by afixture), the shape memory material is heat treated, i.e., it is broughtto an elevated temperature for a controlled length of time and thenrapidly quenched so as to return the shape memory material to ambienttemperature. This processing causes the shape memory material to retainits aforementioned “second shape”, even after the device is releasedfrom the fixture. Thereafter, the shape memory material may betransformed from its “second shape” to its “first shape” (e.g., bytemperature transition or by mechanical deformation) and then, whendesired, automatically returned to its “second shape” (e.g., by adifferent temperature transition or by releasing the mechanicaldeformation).

Thus it will be seen that, in connection with the present invention,when the novel device is to be formed out of a shape memory material,with the “second shape” being the aforementionedlongitudinally-contracted, substantially three-dimensional configurationand the “first shape” being the aforementioned longitudinally-expanded,substantially linear configuration, the device must be held in its“second shape” on a fixture while the shape memory material isappropriately heat treated (e.g., heated and then rapidly quenched) sothat the device will thereafter retain its “second shape” when it isreleased from the fixture.

In one preferred form of the present invention, the elastic filamentcomprises shape memory material wire (e.g., Nitinol wire), and the noveldevice is formed by first winding the elastic filament around aplurality of surface features (e.g., posts) disposed on (or in) athree-dimensional body (i.e., “the fixture”), and then appropriatelyheat treating the elastic filament while it is retained on the fixtureso that the elastic filament will retain the desired “second shape”(i.e., the aforementioned longitudinally-contracted, substantiallythree-dimensional configuration) when the device is released from thefixture. See, for example, FIG. 108, which shows a novel device 400comprising a single elastic filament 405, wherein the elastic filament405 is wound around a plurality of posts 410 which are mounted on athree-dimensional (e.g., spherical) body 415 (i.e., “the fixture”) forappropriate heat treatment. It will be appreciated that this approachmay be used regardless of whether the single elastic filament hasdistinct first and second ends or has its first and second ends unifiedwith one another (e.g., by welding, by banding, etc.) so as toeffectively form a continuous, closed loop.

The foregoing manufacturing approach, which may sometimes be referred toherein as the “winding” approach, is highly advantageous since it allowsthe elastic filament to be formed out of shape memory material wire(e.g., Nitinol wire), which is well known in the art. As a result, it ispossible to take advantage of the substantial body of general knowledgewhich already exists with respect fabricating, handling and heattreating shape memory material wire (e.g., Nitinol wire).

However, as noted above, this “winding” approach requires that theelastic filament be wound around surface features (e.g., posts) disposedon (or in) a three-dimensional body (i.e., “the fixture”).

In another preferred form of the present invention, there is provided analternative manufacturing approach, which may sometimes be referred toherein as the “flat-to-3D” approach. Generally described, with this“flat-to-3D” approach, and looking now at FIGS. 109-111, a flat sheet420 of shape memory material (e.g., Nitinol) is patterned so as tocreate at least one, and preferably a plurality of, single filament,two-dimensional interim structures 425 (FIGS. 109 and 110). These singlefilament, two-dimensional interim structures 425 are thereafter released(i.e., separated) from the flat sheet 420 (e.g., by severing anattachment tab 430 connecting the single filament, two-dimensionalinterim structure 425 to the flat sheet 420 of shape memory material),and then mounted onto an appropriate three-dimensional body (i.e., “thefixture”) for heat treating (i.e., heating and rapidly quenching), sothat the single filament, two dimensional interim structure 425 willthereafter assume the desired “second shape” (i.e., the aforementionedlongitudinally-contracted, substantially three-dimensionalconfiguration) 435 (FIG. 111) when the device is thereafter releasedfrom the fixture, whereby to provide the desired shape for the device.

More particularly, the aforementioned longitudinally-contracted,substantially three-dimensional configuration 435 of the device (FIG.111) is projected into a corresponding two-dimensional configuration 440(FIG. 112) for the device. This two-dimensional projection 440 of thedevice (FIG. 112) corresponds to the single filament, two-dimensionalinterim structure 425 referred to above. This two-dimensional projection440 of the device (FIG. 112) is then used to fabricate the singlefilament, two-dimensional interim structure 425 from a flat sheet 420 ofshape memory material.

In one preferred form of the invention, and looking now at FIG. 113, aplurality of these single filament, two-dimensional interim structures425 are produced from one flat sheet 420 of shape memory material. Thismay be effected using a number of different fabrication techniques,including chemical etching, laser cutting, etc. Chemical etching iscurrently generally preferred, and may yield the single filament,two-dimensional interim structures 425 shown in FIGS. 114, 116 and 118,with each individual single filament, two-dimensional interim structure425 being attached to the flat sheet 420 of shape memory material by atleast one attachment tab 430. Preferably the single filament,two-dimensional interim structure 425 carried by the flat sheet 420 ofshape memory material is then electro-polished, which is a “reverseplating” process that electrochemically removes additional material.This occurs preferentially at sharp corners, where the electrical fieldsare the strongest, thereby advantageously rounding off sharp corners.See, for example, FIGS. 115, 117 and 119, which show the etchedstructures of FIGS. 114, 116 and 118, respectively, afterelectro-polishing.

Thereafter, the single filament, two-dimensional interim structure 425is dismounted from the flat sheet 420 of shape memory material (e.g., bysevering the one or more attachment tabs 430 holding the singlefilament, two-dimensional interim structure 425 to the flat sheet 420 ofshape memory material), and then the freed single filament,two-dimensional interim structure 425 is mounted on an appropriatethree-dimensional fixture so that the single filament, two-dimensionalinterim structure 425 assumes the desired “second shape”, i.e., theaforementioned longitudinally-contracted, substantiallythree-dimensional configuration.

See, for example, FIGS. 120-125, which show a two-part fixture 450comprising a male half 455 and a female half 460. Male half 455comprises a three-dimensional (e.g., spherical) body 465 having aplurality of posts 470 mounted thereon. Female half 460 comprises athree-dimensional (e.g., spherical) cavity 475 which is the substantialinverse of at least a portion of three-dimensional body 465. The singlefilament, two-dimensional interim structure 425 is set on thethree-dimensional body 465 using posts 470 to stabilize the singlefilament, two-dimensional interim structure, and then the two halves455, 460 are brought together so as to force the single filament,two-dimensional interim structure 425 to assume the desired “second”shape (i.e., the aforementioned longitudinally-contracted, substantiallythree-dimensional configuration).

With the single filament, two-dimensional interim structure 425restrained in the desired “second shape” (i.e., the aforementionedlongitudinally-contracted, substantially three-dimensionalconfiguration), the device is heat treated (i.e., it is appropriatelyheated and then rapidly quenched to ambient temperature) so as to“train” the device to assume the desired “second shape” (i.e., thelongitudinally-contracted, substantially three-dimensionalconfiguration). The device may thereafter be dismounted from thethree-dimensional fixture, whereby to provide the structure 435 shown inFIG. 111, and thereafter used in the manner previously discussed.

In connection with the foregoing, the following additional points shouldbe appreciated.

Device Design.

In certain circumstances, it may be desirable to form certain portionsof the novel device with a stiffer characteristic than other portions ofthe device, which may require a more flexible characteristic. By way ofexample but not limitation, by forming certain portions of the devicewith a stiffer characteristic, the ability of the device to return toits longitudinally-contracted, substantially three-dimensionalconfiguration 435 (FIG. 111) may be enhanced. This can be extremelyuseful where the device is made with a relatively thin elastic filamentin order to fabricate a relatively small device, since a relatively thinelastic filament may not generate adequate return forces to restore thedevice to its longitudinally-contracted, substantially three-dimensionalconfiguration 435 (FIG. 111) when the device is disposed in a bloodvessel (or vessels).

One way of providing regions of greater or lesser stiffness is byforming the elastic filament with regions of thicker or thinnerdimensions. This is relatively easy to do with the “flat-to-3D” approachof the present invention, where the single filament, two-dimensionalinterim structure 425 is being formed out of a large flat sheet 420 ofshape memory material. In this case, the regions of greater stiffnessare formed thicker (e.g., wider) and the regions of lesser stiffness areformed thinner (e.g., narrower).

By way of example but not limitation, where etching is used to fabricatethe single filament, two-dimensional interim structure 425 from a flatsheet 420 of shape memory material, the process is essentially asubtractive process where material is etched away. As a result,different thicknesses (e.g., widths) may be provided for the elasticfilament by etching away more or less material from flat sheet 420. See,for example, FIG. 110, where portions 480 of single filament,two-dimensional interim structure 425 have a greater thickness (e.g.,width) than portions 485 of single filament, two-dimensional interimstructure 425. This construction is retained in thelongitudinally-contracted, substantially three-dimensional configuration435 (FIG. 111) which is produced from the single filament,two-dimensional interim structure 425 after appropriate heat treatmenton a fixture (e.g., the two-part fixture 450 shown in FIGS. 120-125).

Another way of forming regions of greater or lesser stiffness is byforming the elastic filament with regions of differing cross-section. Byway of example but not limitation, where the device has a roundcross-section, the device will tend to bend equally well in alldirections when the bend occurs at that cross-section, but where thedevice has a rectangular cross-section, the device will tend to bendpreferentially in certain directions when the bend occurs at thatcross-section. Accordingly, it is possible to form regions of greater orlesser stiffness by intentionally varying the cross-section of thedevice along its length, whereby to provide the device with themechanical properties desired for various segments of the device. Again,this is relatively easy to do with the “flat-to-3D” approach of thepresent invention, where the single filament, two-dimensional interimstructure 425 is being formed out of a large flat sheet 420 of shapememory material via a subtractive process, since the subtractive processcan be used to provide various cross-sections at different points alongthe device.

Furthermore, the material (e.g., metallurgical) properties of the flatsheet 420 of shape memory material are not necessarily the same in alldirections. By way of example but not limitation, the shape memorymaterial may be stronger in one direction than in another direction,e.g., the shape memory material may be stronger in the direction inwhich it is rolled during the manufacturing process than in the opposingdirection. By taking such factors into account when forming the singlefilament, two-dimensional interim structure 425 from the flat sheet 420of shape memory material, it is possible to take advantage of varyingmaterial properties, e.g., so as to construct devices which can bebetter stretched or compressed in selected directions.

Etching.

Etching may be conducted from one side of flat sheet 420 or from bothsides of flat sheet 420, either concurrently or serially. Where etchingis effected from both sides of flat sheet 420, the resultingcross-sectional shape of the elastic filament may somewhat resemble ahexagon.

As a general rule, the etching process requires the provision of a spacebetween the “solid” portions (i.e., the filament runs) of the device,where this space is approximately equal to the thickness of the flatsheet 420.

In one preferred form of the invention, flat sheet 420 is approximately0.004 inch thick. In another form of the invention, flat sheet 420 isapproximately 0.0053 inch thick.

Electro-Polishing.

As noted above, electro-polishing is a “reverse plating” process whichelectrochemically removes material. It preferentially takes materialaway from sharp corners, where the electrical fields are the strongest.Rounding sharp corners is believed to be beneficial for the presentinvention, since it provides a gentle radius where the device touchestissue, and it reduces stress concentrations in the elastic filament. Inaddition, the rounding of corners will tend to bring the cross-sectionof the elastic filament to a near-circular shape, which will tend toincrease ease of bending in any direction.

Electro-polishing removes material thickness as well. As a simple ruleof thumb, electro-polishing creates about a 2× corner radius for a 1×decrease in material thickness. As a result, a 0.0005 inch thicknessdecrease results in a 0.001 inch radius on an outside corner.

FIGS. 126, 128 and 130 are views showing electro-polishing to 0.00415inch thick, and FIGS. 127, 129 and 131 are views showingelectro-polishing to 0.0039 inch thick.

Electro-polishing can also change the surface properties of the shapememory material. By way of example but not limitation, flat sheet 420typically has machining marks and other marks from the Nitinol sheetfabrication process. These marks may be minimized or diminished in theelectro-polishing process.

Electro-polishing can also change the surface finish of the device.Generally, the electro-polishing smooths the surface and makes it morecorrosion resistant.

Tailoring the Cross-Section of the Device.

It should be appreciated that the cross-section of the device can affectthe mechanical properties of the device when the device is subjected tovarious forces. By way of example but not limitation, where the devicehas a round cross-section, the device will tend to bend equally well inall directions when the bend occurs at that cross-section. By way offurther example but not limitation, where the device has a rectangularcross-section, the device will tend to bend preferentially in certaindirections when the bend occurs at that cross-section. Accordingly, inone form of the present invention, the device has a cross-section whichis intentionally varied along its length in accordance with themechanical properties desired for various segments of the device.

It will be appreciated that a desired cross-section can be achieved byappropriately selecting and implementing a specific manufacturingprocess, e.g., where etching is used to form the device, various etchingparameters (including masking) can be adjusted so as to form a desiredcross-section, and/or where electro-polishing is used to form thedevice, various electro-polishing parameters (including masking) can beadjusted so as to form a desired cross-section, etc.

Forming the Final Three-Dimensional Structure from the Two-DimensionalInterim Structure.

As noted above, the present invention comprises transforming thetwo-dimensional interim structure 425 (FIG. 110) into the finalthree-dimensional structure 435 (FIG. 111). As this transformationoccurs, the spacing between the filament lengths (i.e., runs) of thetwo-dimensional structure 425 is reduced in the three-dimensionalstructure 420. This is because the filament lengths move closer togetheras the device transforms from a two-dimensional structure to athree-dimensional structure (e.g., as the filament lengths move from aplanar arrangement to a spherical arrangement). As result, the designmust provide adequate space between the filament lengths in thetwo-dimensional structure so as to permit appropriate spacing of thefilament lengths in the three-dimensional structure.

MODIFICATIONS

It will be appreciated that still further embodiments of the presentinvention will be apparent to those skilled in the art in view of thepresent disclosure. It is to be understood that the present invention isby no means limited to the particular constructions herein disclosedand/or shown in the drawings, but also comprises any modifications orequivalents within the scope of the invention.

What is claimed is:
 1. A method for making a device for causingthrombosis of an aneurysm, wherein said device comprises a singleelastic filament configurable between (i) an elongated, substantiallylinear configuration, and (ii) a longitudinally-contracted,substantially three-dimensional configuration, said method comprising:providing a sheet of shape memory material; producing a single filament,two-dimensional interim structure from said sheet of shape memorymaterial, wherein said single filament, two-dimensional interimstructure is temporarily held to said sheet of shape memory material byan attachment tab; mounting said single filament, two-dimensionalinterim structure to a fixture so that said single filament,two-dimensional interim structure is transformed into saidlongitudinally-contracted, substantially three-dimensionalconfiguration; and heat treating said single filament, two-dimensionalinterim structure while it is mounted to said fixture so as to producesaid single elastic filament in its longitudinally-contracted,substantially three-dimensional configuration.
 2. A method according toclaim 1 wherein said single filament, two-dimensional interim structureis produced from said sheet of shape memory material by etching.
 3. Amethod according to claim 1 wherein said single filament,two-dimensional interim structure is produced from said sheet of shapememory material by laser cutting.
 4. A method according to claim 1further comprising the step of electro-polishing said single filament,two-dimensional interim structure before it is mounted to said fixture.5. A method according to claim 4 wherein said step of electro-polishingsaid single filament, two-dimensional interim structure is performedwhile said single filament, two-dimensional interim structure is stillattached to said sheet of shape memory material.
 6. A method accordingto claim 1 wherein said fixture comprises a three-dimensional body.
 7. Amethod according to claim 6 wherein said three-dimensional bodycomprises surface features for releasably retaining said singlefilament, two-dimensional interim structure on said three-dimensionalbody.
 8. A method according to claim 7 wherein said surface featurescomprise posts mounted to said three-dimensional body.
 9. A methodaccording to claim 1 wherein said fixture comprises a two part fixturecomprising a male half and a female half.
 10. A method according toclaim 9 wherein said male half of said fixture comprises surfacefeatures for releasably retaining said single filament, two-dimensionalinterim structure on said male half of said fixture.
 11. A methodaccording to claim 9 wherein said surface features comprise postsmounted to said male half of said fixture.
 12. A method according toclaim 1 wherein said step of heat treating comprises heating followed byquenching.
 13. A method according to claim 1 wherein said singlefilament, two-dimensional interim structure comprises a continuousclosed loop.
 14. A method according to claim 1 wherein said singlefilament, two-dimensional interim structure comprises two distinct ends.15. A method according to claim 14 comprising the additional step ofunifying the two distinct ends so as to form a continuous closed loop.16. A method according to claim 15 wherein the two distinct ends areunified by welding.
 17. A method according to claim 15 wherein the twodistinct ends are unified by banding.
 18. A method according to claim 1wherein a plurality of single filament, two-dimensional interimstructures are produced from said sheet of shape memory material.
 19. Amethod according to claim 1 wherein said single filament,two-dimensional interim structure is released from said sheet of shapememory material by severing said attachment tab.
 20. A method accordingto claim 1 wherein said single filament, two-dimensional interimstructure has a width which varies along its length.
 21. A methodaccording to claim 1 wherein said single filament, two-dimensionalinterim structure has a thickness which varies along its length.
 22. Amethod according to claim 1 wherein said single filament,two-dimensional interim structure has a cross-section which varies alongits length.
 23. A method according to claim 1 wherein said singlefilament, two-dimensional interim structure comprises a cross-sectioncomprising flat edges.
 24. A method according to claim 1 wherein saidsingle filament, two-dimensional interim structure comprises across-section comprising flat edges and rounded edges.
 25. A methodaccording to claim 1 wherein said single filament, two-dimensionalinterim structure comprises a cross-section which is circular.
 26. Amethod according to claim 1 wherein said single filament,two-dimensional interim structure comprises a cross-section which isovoid.
 27. A method according to claim 1 wherein said sheet of shapememory material has different material properties in differentdimensions.
 28. A method according to claim 1 wherein the shape memorymaterial is selected from the group consisting of: a nickel titaniumalloy, a copper-based alloy, an iron-based alloy, and a shape memorypolymer.
 29. A method according to claim 28 wherein the nickel titaniumalloy comprises nitinol.
 30. A method for making a device for causingthrombosis of an aneurysm, wherein said device comprises a singleelastic filament configurable between (i) an elongated, substantiallylinear configuration, and (ii) a longitudinally-contracted,substantially three-dimensional configuration, said method comprising:providing a filament of shape memory material, wherein said filament isproduced from a sheet of shape memory material, and further wherein saidfilament is temporarily held to the sheet of shape memory material by anattachment tab; mounting said filament of shape memory material to afixture so that said filament is transformed into saidlongitudinally-contracted, substantially three-dimensionalconfiguration; and heat treating said filament so as to produce saidsingle elastic filament in its longitudinally-contracted, substantiallythree-dimensional configuration.
 31. A method according to claim 30wherein said fixture comprises a three-dimensional body having surfacefeatures for releasably retaining said filament of shape memory materialon said three-dimensional body, and further wherein mounting saidfilament of shape memory material to said fixture comprises winding saidfilament of shape memory material around said surface features.
 32. Amethod according to claim 31 wherein said surface features compriseposts mounted to said three-dimensional body.